In a typical radio communications system, setting up a push-to-talk (PTT) call, transmitting the initial session initiation protocol (SIP) INVITE in a short data burst (SDB) or a RECONNECT with a short data burst over the reverse enhanced access channel (R-EACH) can significantly reduce end-to-end call set-up time. However, these messages are significantly longer, perhaps five to six times longer, than other types of access channel messages. Consequently, INVITE and RECONNECT are much more susceptible to transmission errors and therefore require higher data rates over the reverse enhanced access channel, up to 38.4 Kbps. The higher data rates in turn require higher transmit power. Because the mobile stations have limited available transmit power, the performance of the communications system becomes reverse link limited when the mobile station is near the edge of a cell sector.
Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions, sizing, and/or relative placement of some of the elements in the figures may be exaggerated relative to other elements to clarify distinctive features of the illustrated embodiments. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of the illustrated embodiments.